This invention relates to a character recognition system utilizing a pattern matching method.
In a standard pattern matching method, the character recognition is achieved by comparison of a pattern of an input character with those of a plurality of predetermined standard masks. For this purpose, a great number of standard masks are provided; for example, at least 10 different masks for numeric characters, and 26 different masks for the letters of the alphabet. These standard masks are stored in a standard computer memory means. During the recognition cycle, the stored standard masks are sequentially read out and compared with the input pattern, to count the number of mask elements (or meshes) which are or are not coincident with the input pattern. Therefore, in the pattern matching methods of the prior art, operational time frame of the recognition cycle is increased with an increase of the standard masks.
To shorten the operational time frame, an improved pattern matching character recognition system was proposed in Japanese Patent Disclosure No. 53-133335. In the method of the disclosure, "black" and "white" meshes in the standard masks are each stored in different standard mask memories as logical 1's. In each of the standard mask memories, the meshes having the same position in the standard masks are stored at the same bit position, e.g., at the same row. The comparisons of the input pattern with the standard masks are achieved simultaneously (or in parallel) by reading out the standard mask meshes stored at the same rows of the standard mask memories. The selection between black mesh and white mesh standard mask memories is controlled in response to the pattern content of the input character.
Although the recognition cycle can be achieved at higher speeds than heretofore possible by this improved character recognition system, the memory construction is not satisfactory in that it is too large; that is, the memory construction can and should be reduced in order to increase available memory.
It is, therefore, an object of this invention to provide a small-sized character recognition system.